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The paper deals with the post-embryonic development of the five most common pandalids in British Columbia, namely. Pandalus danae, Pandalus borealis, Pandalus hypsinotus, Pandalus platyceros, and Pandalopsis dispar, in greatest detail with the first species, with which the others are compared. The first stage of post-embryonic development was obtained for each species by hatching the eggs in the laboratory. Later larval stages were obtained from plankton collections, and all known stages were described and illustrated. All five species tend to be more fully developed on hatching than is normal for Caridea. The individuals of each species all undergo a change of sex, functioning first as males and later as females, the time spent in each phase varying in different species. Pandalus danae spends about eighteen months in the male phase, P. borealis and P. hypsinotus each spend about thirty months, while P. platyceros and Pandalopsis dispar are about forty-two months old before they begin to change to the female phase. The rate of growth is similar in all for the first summer, and then begins to vary. Differences in the rates of growth of the different species may partly be caused by variations in the rapidity with which they mature as males, and in the length of time spent in the male phase. Only for Pandalus danae has the rate of increase of weight been considered, and it was found to increase approximately as the cube of the length.

Little is known of the larvac of the Pandalidac as is shown by Gurney (1939) in his Bibliography of the Larvae of Decapod Crustacea. Berkeley (1930,1938) describes the life histories of several species of Pandalus and of Pandalopsis dtspar from British Columbia, and Gurney (1937) the larvae and post-larvae of Chlorotocella, but beyond these the information is fragmentary. Sars’ (1900) work on Pandalus borealis and P. bonnieri was formerly regarded as typical of pandalid larvae but these were proved to be Caridion (Lebour, 1930). Sars (1900), however, described in part in an excellent manner the larvae of Pandalus montagui and Pandalina brevirostris and Stephensen (1935) the early larvae of Pandalus propinquus.

Comparative studies of hyperglycemic hormone (HGH) in crustaceans furnish evidence for species differences in molecular structure of HGH. This evidence consists of: interspecific differences in hyperglycemic response to cross tests with injected extracts; differences in elution volumes after chromatography on DEAE-cellulose between Cancer, Pandalus , and Orconectes material; different mobilities on gel acrylamide electrophoresis of HGH from the three species. Steps in the purification are described.

[Description des stades zoe de Pandalina brevirostris (Rathke), Dichelopandalus bonnieri (Caullery), Pandalus propinquus G. O. Sars et Pandalus montagui Leach d'apres des eclosions en laboratoire et des echantillons provenant de peches planctoniques. Les larves de P. propinquus n'avaient pas ete correctement identifies jusqu'a present. Un resume des connaissances publiees sur les larves de Pandalidae est donne, et l'evolution des larves et des adultes a l'interieur de la famille est discutee., Description des stades zoe de Pandalina brevirostris (Rathke), Dichelopandalus bonnieri (Caullery), Pandalus propinquus G. O. Sars et Pandalus montagui Leach d'apres des eclosions en laboratoire et des echantillons provenant de peches planctoniques. Les larves de P. propinquus n'avaient pas ete correctement identifies jusqu'a present. Un resume des connaissances publiees sur les larves de Pandalidae est donne, et l'evolution des larves et des adultes a l'interieur de la famille est discutee.]

Synthetic Pandalus red pigment-concentrating hormone was effective in concentrating the pigment in the erythrophores of the fiddler crab Uca pugilator and the dwarf crayfish Cambarellus shufeldti. However, this hormone had no effect on the melanophores of the crab or the leucophores of the crab and crayfish. These results are in accord with the hypothesis that in the fiddler crab and the dwarf crayfish, respectively, the hormonal control for each type of chromatophore is different.

The prawn, Pandalus kessleri, is commercially important for canning purpose in East and Notth-Eastern coasts of Hokkaido. Dealing with a large number of specimens taken monthly from Notsuke Bay and Lake Saroma, a bionomics has been carried out, in which the follow-ing 8 items fundamental for conservation of the prawn were treated, viz., growth, weight-le-ngth relationship, secondary sexual characters, sex-reversal, size and numder of eggs produced, spawning season, larvae, food and digestive organs. Derail account of these items has been set fotth in English on the Journal of the Tokyo University of Fisheries, 38 (1), 1 ?? 26, 1951. Wherefore one would be referred to it.

The biology of whiting in Manx waters has been investigated at different stages of the life-cycle, with special reference to their diet. Planktonic postlarvae occurred chiefly in May, these measured between 4.5 and 16.5 mm, and had fed chiefly on Pseudocalanus. Larger whiting (between 21 and 52 mm) were taken in association with Rhizostoma. They were approximately 2–4 months old, and had fed on copepods supplemented with Hyperia and euphausiid furcilia. Immature whiting 77 mm long appeared in July in a shallow sandy bay—a nursery area. The fish were about 4–5 months old, and fed on swarming amphipods, isopods and mysids after dark, when these organisms were free-swimming. This diet was supplemented to an appreciable extent during the following April-June quarter by the inclusion of juvenile Ammodytes. After staying for nearly 1 year in the nursery area, the bulk of the fish appear to migrate to the open sea.In the open-sea habitat, the immature fish fed chiefly on euphausiids, decapods and sprats—nektonic forms particularly. These whiting are themselves eaten by larger whiting in the same habitat. Adult whiting (over 220 mm) were taken only offshore, and fed chiefly on euphausiids, Crangon, Pandalus, Pasiphaea, Clupea and gadoids. A few samples taken off the east coast of I.o.M. indicated that the whiting are capable of feeding on infauna and plankton in an environment deficient in active epifauna and nekton. The whiting is an active feeder throughout the year.Two length-weight relationships have been calculated for Manx whiting: nursery-area, and open-sea fish—the latter gain weight more rapidly than the former would be expected to do.

Pandalus bonnieri is a dioecious species and no protandrous hermaphrodites have been seen.The breeding season and incubation period for P. bonnieri are described.The number of eggs laid increases with the size of the female. At 16 mm. carapace length the number of eggs is c. 1000 and at 24 mm. carapace length the number of eggs is c. 4000. The number for a single mm. size group varies roughly by ±10%.Both male and female P. bonnieri become sexually mature at about 18 months, and in the Clyde seldom live beyond 3 years of age.The colour of the eggs in P. bonnieri is sage green, in P. borealis blue green, in P. montagui light emerald green and in P. propinquus fawn.Juvenile P. bonnieri can be separated into males and females by the shape of the pleopods within 4–6 months of hatching.

BERKELEY1,2 has reported that the pandalid shrimps are protandric hermaphrodites. Until recently little work had been done to identify the intrinsic agents which are active in the sexual differentiation of these animals. During the male phase of Pandalus borealis3,4 an androgenic hormone is produced by a pair of epithelial organs on the distal end of the vasa deferentia. This hormone is responsible for the maintenance of the testis and the male secondary sex characteristics. These endocrine organs, the androgenic glands, disappear at a certain stage of the shrimp's life cycle and the animal is transformed into a functional female.

A fungus disease of the pandalid shrimp, Dichelopandalus leptocerus, is described and a partial life cycle is proposed. The causal agent is a chytridlike phycomycete. Infection is limited to the branchial lamellae in which thallus development causes necrosis of the lamellar tissue matrix.

White pigment concentrating hormone (WPCH) was isolated from eyestalks of Crangon and of Pandalus by gel filtration on columns of Sephadex G-25. After such isolation the hormone was partially purified by partition between butanol and water phases. WPCH is rapidly inactivated by trypsin and by pronase, indicating that the hormone is most likely a peptide. Comparison of the elution volumes of WPCH from Crangon and Pandalus indicates that the molecular weights are similar.

Synthetic Pandalus red pigment-concentrating hormone and extracts of eyestalks from Uca pugilator and Palaemonetes vulgaris were passed through a column of Bio-Gel P-6. In each instance the elution volume of the fraction that provided maximal concentration of the red chromatophoric pigment of Palaemonetes was the same, indicating thereby that these three red pigment-concentrating hormones have either the same or nearly the same molecular size.

Johann Heinrich von Thunen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung – Information on Fishery research in 2010

A new separation procedure yields about 60% recovery of light-adapting distal retinal pigment hormone (DRPH), contrasted with 0.4% for an earlier procedure. Aqueous extracts of Pandalus eyestalks are brought to pH 3.0 with acetic acid, and the supernate is chromatographed on G-25 Sephadex with 0.1 M acetic acid. DRPH is found in the first of seven designated peaks. When tested on the dispersed erythrophores of eyestalkless Palaemonetes vulgaris, Peak I shows no erythrophore-concentrating hormone (ECH). ECH activity occurs in Peak IV, which in turn has no significant DRPH activity; the two hormones thus appear to be different molecules. Paper chromatography of Peak IV reveals two or three ninhydrin-staining spots. The hormone MDH, dispersor of melanophore pigment in destalked Uca pugilator, occurs in Peak I. The two chromatophorotropins thus appear to be distinct molecular species. Paper chromatography of Peak I shows a single spot (ninhydrin) which remains at the origin. Both paper electrophoresis and preliminary examination in the analytical ultracentrifuge, however, indicate the possibility of two components in Peak I and hence no statement can yet be made about the molecular identity of MDH and DRPH.

Johann Heinrich von Thunen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung – Information on Fishery research in 2010

Earlier work in this laboratory showed that the biological activity of vitamin A extracts from some marine Crustacea was lower than that indicated by the Carr–Price test. It was suggested that this discrepancy might have been due to the presence of cis-isomers of vitamin A, which give the same quantitative colour reaction in the Carr–Price test but are biologically less active than all- trans vitamin A. In this paper, the isomer composition of the vitamin A of two euphausiid Crustacea, Meganyctiphanes norvegica (M. Sars) and Thysanoessa raschii (M. Sars), and of three decapod Crustacea, Pandalus bonnieri Caullery , P. borealis Kroyer and P. montagui Leach, is reported. The percentages of ‘fast’ (all- trans and 9- cis vitamin A) and ‘slow’ (13- cis , 9:13-di- cis , neo- b and neo- c vitamin A) reacting isomers were calculated from the rate of combination of vitamin A preparations from these species with maleic anhydride in benzene solution. Hindered cis -isomers were detected by their rapid isomerization with iodine, which results in an increase of the wavelength of the ultra-violet absorption maximum and a large increase in extinction, and by a high value for the ratio (maximum extinction in the Carr-Price test)/ (maximum extinction in the ultra-violet). The retinenes of these vitamin A isomers were allowed to react with opsin in the dark and the neo- b retinene present was measured by the formation of rhodopsin. In all five species studied, the hindered cis -isomer, neo- b vitamin A, was the most abundant form and constituted 53 to 90 % of the total vitamin A. Another hindered cis -isomer, neo- c vitamin A, not so far reported from natural sources, was isolated from extracts of M . norvegica and T . raschii by fractional chromatography. It constituted about 5% of their total vitamin A. The remainder of the vitamin A was mostly in the all- trans form. The calculated biological activities of these mixtures of isomers agreed well with the results of biological assays with rats. As the vitamin A is located in the eyes of these Crustacea, it is possible that it has a visual function. The significance of these findings in relation to the vitamin A food chain in the sea is discussed, and it seems probable that the predators of the Crustacea are able to convert neo- b vitamin A into the all - trans form.

The ultrastructure of the chromatophores of two decapod crustaceans, Crangon crangon and Pandalus borealis, is investigated. The pigment appears macroscopically as small units, so-called chromatosomes. These contain separate chromatophores of different colors, and each color is composed of several chromatophores. Each chromatophore contains pigment granules, tubuli (ca. 210 A), a network of cisternae of the endoplasmic reticulum, and mitochondria. A close contact exists between the cisternae and the pigment granules. The tubuli are arranged in thick bundles in the chromatophore extensions. The pigment granules of chromatophores of different colors are found to be structurally different. This phenomenon, as well as the structure of the whole chromatophore, is related to the vertebrate chromatophores.

Johann Heinrich von Thunen-Institute, Federal Research Institute for Rural Areas, Forestry and Fisheries began publishing the Informationen aus der Fischereiforschung – Information on Fishery research in 2010

PROTANDROUS hermaphroditism, or the changing from the male sex to the female during the growth of the same individual, is now well known in certain northern-hemisphere commercial prawns of the family Pandalidae, namely, species of the genera Pandalus (P. borealis1, P. danae1, P. hypsinotus1, P. kessleri2, P. montagui3 and P. platyceros1) and Pandalopsis (P. dispar1). In the Hippolytidae, this phenomenon has been demonstrated in two European and Mediterranean species of Lysmata, namely, L. seticaudata (the first decapod in which protandry was recognized4) and L. nilita5.